1. Field of the Invention
The present invention relates to an electronic keyboard musical instrument having a sound board that is caused to vibrate to generate musical tones.
2. Description of the Related Art
Electronic keyboard musical instruments have been improved so as to be capable of faithfully reproducing natural musical tones of a spreading feeling produced by acoustic musical instruments. However, there are still some differences in sound between electronic keyboard musical instruments and acoustic musical instruments.
Specifically, an acoustic musical instrument produces not only musical tones sounded by vibrations of vibrating members such as strings, but also sounds generated by musical instrument components that are made in contact with one another when an operator such as a key is driven. The resonance of a sound board and other component of the-musical instrument can also produce sounds. Moreover, the aforementioned various sounds complicatedly interact with one another to produce further sounds. On the other hand, such complicated sounds cannot fully be expressed by existing electronic keyboard musical instruments.
For example, there is known an electronic keyboard musical instrument in which a tone is generated according to a performance operation of the instrument, and the generated tone is sounded as a performance tone from a speaker. However, musical tones are sometimes sounded by an acoustic musical instrument in a complicated environment in which tones are affected by operative states and operating timings of a keyboard and a pedal of the musical instrument, whereas the known electronic keyboard musical instrument entails a limitation in the reproduction of tones sounded in such a complicated environment. This results in insufficient expression.
Furthermore, another type of electronic keyboard musical instrument has been known in which transducers (vibrating devices) are mounted to a sound board of this musical instrument to cause the sound board to vibrate to thereby output complicated resonance sounds (Japanese Patent Publication No. 2917609 and Japanese Laid-Open Patent Publication (Kokai) No. H05-80748).
However, electronic keyboard musical instruments using transducers as disclosed in the aforementioned Japanese Patent Publications have still been under development, and require further improvements in respect of the required number of transducers and characteristics and installation arrangement of the transducers in order to permit musical tones to be sounded with sufficient volume and freely perform tone quality control.